Don Terrill’s Speed-Talk

LOL :lol: :lol: :lol: Nice first post! Laugh all you want, it's 100% truth. Yep, a flow curve that never backs up will always make more hp & hold that power longer than a head with even a 20cfm stronger flow curve that backs up even .100" lift above valve lift - all else being equal. I've ...

Is US pump e85 actually e *up to* 85? Changing by season and location?

I don't know how a carb would deal with that variability in fuel.

I'm not that up on carb calibration, but I've head of low-mid rpm rich being caused by reversion (but that was at WOT). If it *is* reversion, you'll probably find it hard to calibrate out. Header or cam timing changes might be in order if it's otherwise uncurable.

I've heard of oil dilution being a thing with high alcohol content fuels, which would certainly match "milking and condensation". It was also a concern with high water injection levels in ww2 aircraft. The general solution to keeping it at bay between services was to get the engine and oil...

On our obsolete iron heads: Large electric fan with shroud I'll add to this and say that any air that can go around the core, will. So fill-in panels, foam stuffing, and undertrays are the order of the day here. You can easily double airflow through the core going from "really bad" to &qu...

If you were to make an undertray that went under your engine, it would act slightly as a bash guard and also be really good at stopping loose hoses catching on things in scenario #2.

Also undertrays can have noteworthy aerodynamic benefits in handling and cooling if you do them right.

I've heard an X or H pipe can dramatically alter drone frequency.

Plus, sounds more racecar

Alternatively if it's one specific frequency, quarter wave resonator or "j pipe" can cancel out a narrow frequency range pretty well.

If you've got header choice, small diameter tri-y with a 2" final choke maximum. Expand it after that to whatever, but you can fit 400hp through a pair of 2" chokes without restriction unless you've really messed up before that (by starting too big, usually)… and even if it *was* restricti...

Water pump flow is variable if there's a thermostat, so it can't really be used that way unless you know it's open all the time. If you have relatively constant temp coming out it's probably varying flow. So without some kind of flow meter it's going to be difficult to estimate. Can you measure *pre...

Well that exhaust floor is going to have approximately zero flow on it, ever... Is there anything you can do in the chamber to encourage flow to enter on the long side? With that kind of port it looks like anything you try make enter the short side will disrupt flow. Suppose you could test this on t...

The 8-4-1 doesn't necessarily need to take up "bundle of snakes" kind of room, around the engine at least. Unfortunately the total length still ends up being fairly long so you'd need to run a sim to see how bad or if it's actually out of tune. If I was building an exhaust for mid-range an...

I have read that thread and I agree, they are excellent heads for many different engine needs. There is one thing about those heads I do not like, and its the water jackets in the heads arent very big. This can be a good thing to a porter who wants more area to create volume or a specific shape, bu...

I'm inclined to go for EFI. You'll need it to make it clean and drivable, and "more big" doesn't necessarily mean "more pig" when you don't have booster venturis or manifold wet flow to worry about. A sequential port EFI with modern well-atomising injectors will go a long way in ...

"If you are only relieving it 1-2mm but going deep you're creating a fairly large amount of crevice volume beside the piston that won't burn easily. " Had not considered the crevice volume and potential problems. Actually I was thinking of just grinding it at about a 45* angle, and 3 - 4 ...

Relieving the block to match the combustion chamber has other implications. If you are only relieving it 1-2mm but going deep you're creating a fairly large amount of crevice volume beside the piston that won't burn easily. That's part of the recipe for detonation if there's fuel or oil in there. Do...